The present invention relates generally to earthworking implements and more particularly to harrow assemblies of the type that have a plurality of articulated sections.
In recent years, many trailing type earthworking implements have been developed in which the implement frame is formed in at least three sections with the outer sections pivotally connected to the center or main section through hinge axes that extend generally fore and aft of the direction of travel of the implement. This allows the operator to pivot the outer end sections to a generally vertical position when the implement must be transported along roadways or other restricted areas and the transverse dimension of the implement in a working condition is about three times the transverse dimension of the implement in the transport condition.
One type of implement in which the articulated sections are utilized is a harrow assembly which has a center main frame section and a pair of outer end or wing sections articulated about fore and aft hinge axes on outer ends of the main frame section. One type of multi-section harrow assembly that has found a considerable degree of commercial acceptance incorporates a main shaft or rockshaft that is rotatably supported on the main frame and has a pair of wheels secured to the outer ends of arms that extend from the main shaft. These wheels support the main frame above the ground. Each wing section also has a rockshaft or wing shaft rotatably supported thereon with a single ground engaging wheel on the outer end of the arm fixed to the outer end of the wing shaft. The three shafts are in axial alignment with each other when the frame sections are in end-to-end relation. The respective rockshafts are rotated with respect to the frame to thereby raise and/or lower the wheels with respect to the frame sections to move the implement frame between raised and earthworking positions.
In order to simplify the mechanism for raising and lowering the implement, it has been customary to provide a single drive means between the main frame and the rockshaft for rotation of the main rockshaft and to provide some kind of interconnection means between the main rockshaft and the wing rockshafts so that rotary motion of the main shaft is automatically transmitted to the wing rockshafts.
Various types of proposals have been suggested for providing such interconnection between the main shaft and the wing shafts which will automatically be disengaged when the wing sections are pivoted to a transport position.
While these types of interconnection means have been proven satisfactory for use in field operations, one of the main problems encountered with the interconnection means between the various frame sections is the maintenance cost. Because of the arrangement of the various parts for the interconnecting means in prior art assemblies, considerable wear is encountered in the interconnection means during normal operation which requires frequent repair and/or replacement of parts.